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The Application of NIR Process Analytical Chemistry in Studying Competitive Adsorption Process
Hong-Wei Yang,
Chen-Bo Cai,
Lu Xu,
Lun Li,
Yan-Li Zou,
Yong-Yuan Tao,
Mei-Qiong Wen
Issue:
Volume 7, Issue 3, June 2019
Pages:
80-86
Received:
8 April 2019
Accepted:
21 May 2019
Published:
12 June 2019
Abstract: With an experimental setup of near-infrared process analytical chemistry, a competitive adsorption process of orthoxylene and aniline vapor onto silica gel has been revealed in the paper. The mixture vapor of orthoxylene and aniline has been introduced into a quartz adsorption bed, which was filled with adsorbent of silica gel and monitored continuously by a near-infrared spectrometer. Based on near-infrared spectra recorded during the adsorption process and chemometrics methodologies, the competitive adsorption process has been studied completely as well as clearly: 1) at about 62 minutes the adsorption achieved its equilibrium or stable state with aniline concentration of 0.22 g/g, and without any orthoxylene; 2) othoxylene was adsorbed first, but then rapidly replaced by aniline; 3) the adsorption of aniline resulted from the hydrogen bonds between aniline’s amino groups and silica gel’s silanol groups while that of orthoxylene was due to physical adsorption; 4) aniline was adsorbed vertically on the silica gel but orthoxylene laid evenly; 5) some surface of silica gel was more active for adsorption than others.
Abstract: With an experimental setup of near-infrared process analytical chemistry, a competitive adsorption process of orthoxylene and aniline vapor onto silica gel has been revealed in the paper. The mixture vapor of orthoxylene and aniline has been introduced into a quartz adsorption bed, which was filled with adsorbent of silica gel and monitored continu...
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Corrosion Inhibition of Mild Steel in Sulphuric Acid (H2SO4) Medium of the Stem Extract of Tetrapleura Tetraptera
Rita Oghenenyerhovwo Ididama,
Vincent Ishmael Egbulefu Ajiwe,
Chingbudun Nduadim Emeruwa
Issue:
Volume 7, Issue 3, June 2019
Pages:
87-94
Received:
26 March 2019
Accepted:
9 May 2019
Published:
17 June 2019
Abstract: The inhibitive action of stem extracts of Tetrapleura tetraptera on mild steel corrosion in 1.0M & 5.0M H2SO4 solutions was studied. The stem were dried under room temperature and mechanically ground into powder form. 100g of the stem powder were extracted with a mixture of methanol/water in the ratio of 4:1 using a Soxhlet extractor for 24 hours. The extracts were distilled at 60°C in a water bath until almost the entire methanol evaporated. 4.0g of the methanol extracts were digested in 1000ml of 1M H2SO4 and 5M H2SO4 and left to cool for 24 hours and the resulting solution was filtered and stored in a 1.0L volumetric flask. The stem extracts test solutions were prepared from the stock solution by dissolving 0.5g/L, 1.0g/L, 2.0g/L and 4.0g/L of the extracts in 1L solution of 1M H2SO4 and 5M H2SO4. Phytochemical analysis was carried out and the result showed the presence of some secondary metabolites such as alkoliods, flavonoids, steroids, saponins and tannins. Weight loss (gravimetric) and gasometric techniques were used to determine the inhibition action of the stem of Terapleaura tetraptera. The results showed that stem of Tetrapleura tetraptera can function as good corrosion inhibitor in acid medium. Inhibition efficiencies (%I) of the stem of Tetrapleura tetraptera extracts was found to reach 73.69% & 50.39% for 1.0M H2SO4 while for 5.0M was 83.31% & 79.54% for gravimetric and gasometric analyses respectively. The corrosion inhibition efficiency increased with increase in the concentration of the extracts and decreased with the increase in time and temperature. The corrosion inhibition efficiency exhibited by the Tetrapleura tetraptera stem extracts is attributed to the stronger adsorption of the phytochemicals present in the plant extracts unto the mild steel. The mechanism of adsorption proposed for the Tetrapleura tetraptera stem extracts is physical adsorption. The corrosion inhibition of the stem of Tetrapleura tetraptera extracts followed Langmuir, Tempkin and Freundlich adsorption isotherm for both 1.0M & 5.0M H2SO4.
Abstract: The inhibitive action of stem extracts of Tetrapleura tetraptera on mild steel corrosion in 1.0M & 5.0M H2SO4 solutions was studied. The stem were dried under room temperature and mechanically ground into powder form. 100g of the stem powder were extracted with a mixture of methanol/water in the ratio of 4:1 using a Soxhlet extractor for 24 hours. ...
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Synthesis and Microbial Activity of Manganese (II) and Cobalt (III) Complexes of 3-Methoxy-4-Hydroxyphenylmethyelene (2- Hydroxyphenyl) Amine
Issue:
Volume 7, Issue 3, June 2019
Pages:
95-103
Received:
26 March 2019
Accepted:
30 April 2019
Published:
26 June 2019
Abstract: Transition metal complexes of Mnanganese (II) and Cobalt (III) were synthesized from the Schiff’s base ligand, 3-methoxy-4-hydroxyphenylmethyelene (2-hydroxyphenyl) amine which is derived from vanillin and 2-aminohpenol by the reaction of the metal ions. The Structural features of these complexes were obtained from their elemental analyses, magnetic susceptibility, molar conductance, FT-IR, electronic spectra, and Atomic Absorption Spectroscopic studies. In order to study the binding modes of the ligand (Schiff’s base) with metal ions in the complexes, the FT- IR spectrum of the free ligand was compared with the spectra of its complexes. The spectral data suggest the involvement of phenolic oxygen and azomethane nitrogen in coordination to the central metal ions. On the basis of spectral studies and magnetic susceptibility measurements, an octahedral geometry has been assigned for both complexes. The free ligand and its metal complexes were tested in vitro against bacteria (Escherichia coli, Staphylococcus aureus) and fungi (Aspergillus Niger, Colletotricum) in order to assess their antimicrobial activities. And the results indicated that all compounds are effective against both tested bacteria and fungi though their effects are dose dependent. The free ligand showed higher activities than its complexes in both bacteria and fungi case, which suggests the promising potential of the ligand for both bacterial and fungi test.
Abstract: Transition metal complexes of Mnanganese (II) and Cobalt (III) were synthesized from the Schiff’s base ligand, 3-methoxy-4-hydroxyphenylmethyelene (2-hydroxyphenyl) amine which is derived from vanillin and 2-aminohpenol by the reaction of the metal ions. The Structural features of these complexes were obtained from their elemental analyses, magneti...
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Determination of Short Chain Chlorinated Paraffins in Textile Samples by GC-MS
Zeng Zheng,
Shao Yuwan,
Li Xian,
Du Juan
Issue:
Volume 7, Issue 3, June 2019
Pages:
104-109
Received:
7 May 2019
Accepted:
13 June 2019
Published:
8 July 2019
Abstract: The method of determining short-chain chlorinated paraffins in textiles by GC-MS was established. Short-chain chlorinated paraffins, short for SCCPs, are a mixture of polychlorinated n-alkanes. These high production volume chemicals are widely used as leather coating, plasticizers for PVC and chlorinated rubber and flame retardants for plastics and textile. Due to their toxicity, as well as capacity for bioaccumulation and persistence in the environmental residue, SCCPs have become an obviously environmental issue. The current analytical equipment combination are very expensive and require a lot of laboratory space and advanced skills for operation, a ready-to-use commercially available method with relatively short time and satisfactory sensitivity urge to be established. In this new method, samples were extracted by n-hexane under ultrasonic followed by concentration and constant-volume and then identified by GC-MS and quantified by external standard method. With this method, a good linear relationship was found between 5 μg/mL ~30μg/mL with a linear correlation coefficient (R2) above 0.995. The detection limit for SCCPs by this method was found to be as low as 10mg/kg. The recoveries of SCCPs in textiles at three levels which covers low, media and high concentration ranges are ranged from 82.3% to 106.9% with relative standard deviation (RSD) of 3.41%~7.61%(RSD, N = 6).
Abstract: The method of determining short-chain chlorinated paraffins in textiles by GC-MS was established. Short-chain chlorinated paraffins, short for SCCPs, are a mixture of polychlorinated n-alkanes. These high production volume chemicals are widely used as leather coating, plasticizers for PVC and chlorinated rubber and flame retardants for plastics and...
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